The use of rotatably driven abrasive articles for grinding, cutting and finishing work objects is widespread and very familiar in our industrial societies. Early on, such abrasive articles were affixed to portable rotary power tools such as air motors or the like by placing an internally threaded nut through a centrally located opening in the abrasive article. The nut included a hub portion which fitted into the bore so that a head or flange portion of the nut abutted the underside of the abrasive article. The nut is adapted to be mounted to the threaded spindle of the power tool. Typically a support flange is positioned on the spindle of the power tool between the abrasive article and an annular shoulder formed on the spindle to provide backing support for the abrasive article. Typically the support is made of a metal stamping that is configured to engage the backside of the abrasive article. The direction of rotation of the spindle when the rotary motor is energized is such that the nut will self thread onto the spindle until a tight frictional engagement is provided. Typically the abrasive article when it is spent is removed from the spindle by applying a wrench to the nut. The nut in the prior art conventional assemblies is not permanently affixed to the abrasive article, but rather is intended to be reused when a worn abrasive article is replaced. Also the support flange is not permanently affixed to the abrasive article and also is intended to be reused with new disks. Typical of such prior art abrasive finishing devices and the means of attachment to the power tool are shown in U.S. Pat. Nos. 489,149; 3,596,415; 1,998,919; 566,883; 507,223; 1,162,970; 791,159; 489,149 and 3,210,892.
With these earlier prior art devices, which included the flange and nut, it was very difficult to remove the spent finishing article because of the extreme forces applied to it during operation of the power tool. As above indicated, such removal required the utilization of a wrench or other tool which expended a large amount of time and effort on the part of the user.
Subsequently it became desirable to affix the mount permanently to the abrasive device so that the entire unit may be quickly and easily attached and detached from the drive shaft of the power motor and discarded along with the abrasive article when the abrasive article has been spent. In these types of devices it has become customary to either utilize an adhesive such as an epoxy resin or the like to attach the mounting hub to the abrasive article or alternatively to crimp a portion of the mounting hub to the abrasive article to retain it permanently in place upon the abrasive article and to secure the article rotationally. Various prior art patents showing such devices are U.S. Pat. Nos. 3,136,100; 415,371; 2,278,301; 3,081,584; 3,500,592; 3,800,483; 4,240,230; 4,541,205; 3,041,797; 3,879,178; 1,724,742; 3,912,411; 3,879,178; 3,960,516; 4,026,074; 4,054,425; 4,088,729; 4,322,920; 4,439,953; 4,449,329; 4,601,661; 791,791; 872,932; 2,567,782; 3,136,100; 3,210,892; 3,621,621; 4,924,634; 5,287,659 and 4,760,670. With these devices, where a portion of the mounting structure is permanently affixed to the abrasive article an additional cost is added to the abrasive article, because of the labor in attaching the mount and the discarding of the permanently attached mounting structure.
As a result of the experience in the industry utilizing abrasive devices, it became apparent that there was a need for a reusable mounting structure which will quickly and easily accept the abrasive article without being permanently attached in any fashion to the abrasive article and which at the same time will provide sufficient clamping to maintain the integrity of the abrasive article during operation while allowing easy removal of the abrasive article from the power tool once it has been spent without the necessity of utilizing tools. Such a device is shown in U.S. Pat. No. 6,379,234 which includes a support unit defining a bore with a resiliently deformable member disposed therein which grips the barrel of a retainer nut to hold the mount on the wheel for attachment to the power tool.
The foregoing devices work well for the purpose intended, however, it was discovered that a reusable mount for abrasive devices which could be more positively secured to the abrasive device was desirable. At the same time the abrasive device when spent must be easily removable by hand from the power tool and the mount.